Kimetsu No Yaiba: The Cure
by Homura Tsukoyomi
Summary: This story follows Kamado Tanjiro, a young demon slayer in search for a way to turn his little sister back human. Hikari Katsuki is a girl covered in a shroud of Mystery. She joins the Demon Slayer Corps with a hidden intent.


**Prologue**

**A/N:**

**Hello!!**

**I'm writing a Kimetsu No Yaiba Fanfiction. So this is the prologue. Nothing much happens except introducing the main female character of this story.**

**I don't own the characters of the Demon Slayer.**

**I hope you enjoy this story!**

**\- Homura.**

**••••**

**Tanjirō was the oldest of six kids. He was supposed to be looking after them. That was his job after his father had passed away.**

**It was a burden he was happy to carry in order to provide for his mother and siblings. He said his goodbye to his family as he ventured down the mountain to sell coal to the villagers. It was a quiet descent and he managed to sell everything.**

**On his way back the strange man living at the bottom of the mountain urged him to take shelter for the night since it wasn't safe. Tanjirō had climbed up and down that path thousands of times already. He had an acute sense of smell so if any predators were coming his way he sure as hell could tell long before they reached him.**

**Yet he found himself following the old man who insisted, "Demons hunt at night" the man said. Tanjirō simply humored the stranger as to not offend him.**

**In the morning he returned home, the air was thin, but not too thin. His heartrate inscreased when the scent of blood lingered in the air. His walk turned a full on sprint as he called on his family only to find he no longer had one. They were all murdered. Murdered? Slaughtered...no... They were viciously torn limb from limb.**

**He stood there, his dark red eyes widened from shock, if he could scream he would but his voice was stuck in his throat. There was only one sole survivor. His sister, Nezuko, breathed heavily. Whatever wound inflected on her had stopped bleeding and for that Tanjirō was thankful.**

**He carried her on his back and ran. He ran, tears clouding his vision as he told himself to be strong for her.**

**That was the night everything changed. The night he met one of the demon slayers and came to know that the folk story was more than just a myth but a reality that people were unaware of.**

**Indeed, demons, lived among men and his sister was now one of them.**

**•••**

**On the same day, Yoru stood in front of her father. Beaten and battered by the same man who brought her up. A man she called father but whom she fully knew was nothing of the sort. A cold blooded demon that raised her after he murdered her mother.**

**She was the opposite of Tanjirō, where he had dark red hair, she had bright brown hair almost a sandy yellow colour. Where he had Dark red eyes, she had a bright pink left eye and a greenish yellow one. Tanjirō would always smile but her face was stoic, unmoving.**

**She was calm, unlike her father. He whose temper terrified everyone. But she swore that day that she'll no longer be his puppet. She'll no longer be just someone he abuses for his sick pleasures.**

**"You disgrace me" he spat her way, angered by her lack of reaction. She was like her mother, looked like her mother and behaved as such. Weakness is how he would describe her.**

**"That's nothing new, is it Tou-san?" she kept her eyes closed.**

**"And you dare speak back!" He withdrew his leg back to kick the thirteen year old girl but she stopped his leg without effort.**

**The air suddenly tensed, it was a kick that would have sent anyone flying, no it was one that would have killed anyone her size. Hell, it had killed people double if not triple her size.**

**The adults dared not interfere, not without his order.**

**She got up quietly.**

**"I'll find the answers you refuse to give me, Tou-san".**

**She heard screams of terror in the room once she had left. It wasn't something new. No, indeed this had been her life.**

**She removed the mask she was wearing and greeted the daylight with a small smile. She had always loved the day.**

**"Yoru-sama, shall I pack your things?" Her servant asked.**

**"That won't be necessary." She carried her backpack "I'm all ready"**

**With that, she left the darkness of the house and stepped outside into the light. seemingly, the first time she had done so since her mother passed away.**

**"Hiro-san, aren't you coming?" She looked back.**

**"Hai," the woman bowed and got some of her luggage quickly and followed.**

**The woman kept quiet next to the girl who had short length hair and that looked a lot more like a boy than anything else, specially with her under developed body. It didn't help that the lord of the house always had her dress in boy clothes.**

**"Hiro-san, Tou-san isn't here to be mad." She opened a conversation after hours of silence. "What was the name mother chose for me?"**

**"Yoru-sama, I'm not allowed to-.."**

**"Katsuki..." The girl interrupted "that was it wasn't it? Call me Katsuki-chan from now on"**

**"Hai...Katsuki-chan" she stuttered.**

**"I'm fully aware the man we left behind isn't my real father. I know a lot of things." She glanced at the woman. "Do you know who my real father is?"**

**"No, Yo-...Katsuki-chan. I'm afraid I don't" she small smiled. It was easily read as a lie by the teen who said nothing in return.**

**She wondered how long they would walk in silence. She'd be damned if she tried to open a conversation with this weird girl.**

**Long after the sunset, Katsuki took her sleeping bag and put it on the ground.**

**"Yoru-sama, this is not befitting of a lady"**

**"I am no lady," she reminded her, it was true. The demon was not her real father, therefore she was nothing but a normal low born child.**

**As much as Hiro hated the girl she did as asked. When the girl was finally asleep she got the small blood vial and drank it. This was her mission, to kill Yoru. The child that she had helped raise.**

**She loomed over the body of the teen, insatiable hunger tugging at her tummy. The things she was fantasizing of doing to the girl were beyond terrorizing to humans but to the new demon they were appetizing.**

**This was her reward for being a good servant, she was rewarded immortality. So what if she had to eat humans? There were too many of them in this world to begin with.**

**"Hiro-san" Katsuki looked at her unmoved by the sight in front of her. No she had seen worse, she had seen demons feast right in front of her.**

**"It'll finally be over." She maniacally laughed "your pitiful life will finally end!" She readied herself to take a bite off her meal when she felt her throat close.**

**Then the sickness got worse to where her skin was nothing but blue lumps and she died.**

**Katsuki looked up at the tree branch where she had sensed human presence. The woman wore a pink kimono, her hair black with hints of purple highlights at the tips. Her eyes with the same purple hue, her lips small and red pursed into a fake smile.**

**Shinobu Kochō felt something for the teen in front of her. Fear, yes it had to be that. She was afraid of the _boy_, unknown reason why. The child was human, looked normal. But for someone who was almost eaten alive by a demon, for someone who had just witnessed the impossible, they stood there unmoved by anything.**

**"Do you not have a home?" She wondered.**

**"No"**

**"What's your name?" The woman kept the same smile and gracefully landed in front of the teen. She normally takes in girls but she could look for a home for the boy.**

**"Hikari Katsuki"**

**"Katsuki-kun" she went on to assume it was a boy since the name was unisex.**

**Katsuki didn't bother correct the woman, her whole life she was looked down upon for being born a girl. In all reality, it didn't matter whether people saw her as a girl or a boy.**

**She left with Shinobu, leaving the remains of the demon behind to be obliterated by the sun.**

**This was the beginning of the journey of two unfortunate souls.**

**••••**

**Kochō found the boy a home with Giyū, though he was reluctant to at first as he liked being alone. He hated to admit the Insect Hashira had a strange way of making him do things.**

**He never in a million years thought he'd end up having to babysit a teen _boy_.**

**"Katsuki was it? Come along" he walked, without making a sound.**

**Katsuki followed to the household that belonged to the Mizu Hashira.**

**"Tomioka-sama" his housekeeper bowed to him.**

**"We have a guest. Do tend to _him_. I must go now" he disappeared right after.**

**The housekeeper looked at the child for a while before telling the teen to follow.**

**For two years, Katsuki was in the care of a man she rarely saw. But she didn't sit doing nothing, she trained with the greater goal of joining the Demon Slayer Corps.**

**The next time Giyū was home, he almost choked. In front of him was no longer a boy but a girl.**

**"Ka-katsuki?" He composed himself almost immediately, her left eye always covered by her hair but she wore a black ribbon. She had a short Kimono on with a teal Haori on top of it, thigh high black socks and black gloves.**

**"Hai, Tomioka-san?"**

**He opened his mouth to ask but he deemed it inappropriate to say such a thing to her.**

**"You wanted to talk to me?"**

**"Ha, I want to join the Demon Slayer corps..."**

**"The final exam is open for all so feel free." In all honesty, Giyū didn't care much. It was standard to see large numbers go in only to have as little as ten people succeed "It's not an easy test. You could die"**

**"I'll take the risk" she said and bowed to him walking away.**

**"Why do you wish to join Kisatsutai?"**

**"Because I don't like being a burden. I'd like to pay my debt to you, Tomioka-san." She left.**

**He went to his meeting as if he hadn't just been smacked by the fact Katsuki had been a girl all this time.**

**On the day of the exam, he saw she was wearing boy clothes again, her hair shorter than it was before.**

**"Katsuki" he handed her a short sword "this is made out of the same ore as my sword. Use it for the exam"**

**She accepted it with both hands and thanked him.**

**"This is yours isn't it?" He handed her the mask she used to wear all the time as a child. "I found it with your old belongings" he said. What he meant to say however was 'I looked for it to give it to you' "masks like these are to ward off evil spirits."**

**"Kaasan made it for me" she took it "thank you. I'll bring your sword back intact"**

**"You better" he said coldly, but he was just the slightest bit worried she would get hurt. Because unlike Kochō's little adopted sister, Katsuki was nowhere near properly trained, at least as far as he knew.**

**She climbed up the stairs and waited, a kid with a blue cloud pattern kimono and a fox mask joined last minute.**

**"Thank you for joining us and welcome to the final selection process." The two girls spoke at the same time.**

**And just like that their exam began.**


End file.
